1. Field of the Invention
This invention generally relates to equipment useful for applying a layer of powdered material to an article, and more particularly to an apparatus primarily structured to apply powders to the upper exposed surfaces of flat bottomed articles resting on an article support tray. The flat bottomed articles intended to be powdered by my apparatus are primarily food articles such as cookies and pastries, and non-food articles such as bread dough proofing baskets and molds. The invention is structured for evenly coating the upward facing surface as well as the exposed exterior or interior curved surfaces of an article. The apparatus is also structured in a manner to help maintain the amount of dust suspended in the air around bakery workers at a minimum.
2. Description of the Prior Art
In some commercial bakeries certain types of bread dough are placed into flat bottomed proofing baskets for the rising or proofing stage, with the dough later being removed from the baskets for baking. Proofing baskets are usually made of an open mesh material with the interior of the basket covered with a fabric liner. The basket liner is adapted to help prevent the dough from sticking to the basket. The basket liners must be dusted with a thin coating of dry flour before insertion of the moist dough. The thin coating of flour prevents the dough from sticking to the liner. The flour dusting process for individual proofing baskets with liners is currently being accomplished manually with either a hand held sifter or by hand-throwing small quantities of flour into the liner at various angles. The above described powdering procedures are not only quite time consuming, but the distribution of the flour on the basket liners is often inconsistent, leaving an excessive amount on the bottom of the liners, and not enough on the sides. A small area left un-floured or under-floured on the liner will cause the dough to stick to the liner, making it difficult to remove the dough without tearing or deforming the shape thereof. Proofing baskets and the liners therein are dish shaped having upwardly curved interior sidewalls. With the use of a hand held sifter, or any sifter position above the basket, the powdered material dispensed therefrom falls vertically downward onto the basket liners. When dusting proofing basket liners with a sifter, the vertically falling flour mainly falls onto the interior bottoms of the liners with very little of the flour landing and sticking to the upturned sidewalls of the liners. Also, since the flouring of the basket liners is manually performed in an open room, the air of the room fills with suspended flour dust making the atmosphere unhealthy to breath for the workers, and subject to a possible explosion under certain conditions. Suspended flour and most other powders in the air are considered to form an explosive or hazardous atmosphere which can be ignited with a small spark created by such unexpected elements as a standard light switch.
With certain types of food articles such as cookies, and pastries or the like, it is sometimes desirable to apply a light layer of powdered sugar to the exposed surfaces thereof for both taste and aesthetic reasons. These food articles are generally flat bottomed and have outside edges which curve under toward the flat bottom. These under-curved edges are difficult to apply powders to, and many feel it is desirable to apply powder in this area.
A prior art search was conducted in the U.S. Patent and Trademark Office for devices useful for applying a layer of powdered material to an article, particularly food articles and equipment associated therewith. Of the documents examined, the following teach devices considered somewhat pertinent to my invention, and are generally typical of the state of the art in powdering devices;
On May 29, 1962, H. B. Burt et. al. was issued U.S. Pat. No. 3,036,533 for a method and apparatus for coating food articles with small particles. The Burt device uses conflicting currents of air created by a fan to randomize the direction of movement of the coating particles within a coating chamber toward the articles to be coated. A conveyor belt is employed for moving the articles through the coating chamber.
E. M. Brogden was issued U.S. Pat. No. 1,985,238 on Dec. 25, 1934, for a device used in the treatment of fresh fruit in preparation for market. The Brogden device is designed to apply fine, dust-like particles of wax onto fruit which are later polished with rotating brushes. The wax particles are passed through a sifting device which can be oscillated for downward dispersion of the particles onto the fruit.
Brogden does not detail structuring for evenly dispersing the wax particles onto the sifting screen prior to oscillation. Failing to evenly disperse the particles onto a tray-like sifting device as shown, can lead to an uneven passage of the dust-like particles through the screen. A larger amount of particles fall through the screen at the location the particles are dumped onto the screen relative to the amount dispensed through the outer edges of the screen. This uneven distribution "may" not be important for articles passing through the dusting chamber on a moving conveyor belt, but would be important for articles intended to be dusted which were generally stationary in a dusting chamber. It is also noted the wax particles are dispensed vertically downward which would make coating of curved sides of the fruit difficult were Brogden not employing a continuous conveyor system which rolls the fruit as it passes through the dusting chamber. Brogden further uses rotating brushes to create a cloud or fog of the dust-like particles in the enclosed space.
It is not feasible to rotate or roll certain articles, particularly flat bottomed articles such as proofing baskets, cookies and pastries to name just a few. The rolling of articles can leave marks in the applied powder, and can knock off the dry powder with a small amount of jarring.
It is generally considered undesirable to create clouds of suspended dust even within a dust tight housing since the air-suspended dust will escape through an open door of the housing. With powdering chambers utilizing "dust clouds" and having doors adapted to be opened and closed to retrieve powdered articles, an excessive amount of time must be permitted to pass before opening the door in order to allow most of the powder to settle out of the air.
Although the Burt and Brogden devices are similar in concept, the structuring and functioning of their equipment differs significantly from mine. The conflicting currents of air used in both the Burt and Brogden devices to randomly disperse the coating particles would generally not be effective for coating deep, dish shaped proofing baskets since wind currents have a tendency to avoid flowing into small closed bottom structures like proofing baskets with liners. Although air can and does pass through a proofing basket and liner to a degree, it does not pass all that freely. Also, the intentionally created dust clouds in both the Burt and Brogden apparatuses would take an excessive amount of time to settle, either slowing down the processing, or allowing dust to escape into the atmosphere when a door of the chamber was opened to remove or insert articles in an apparatus such as mine. My apparatus overcomes these and other disadvantages, and provides new and useful benefits to article powdering equipment not previously provided in past art devices structured for similar purposes.